1. Field of the Invention
The present invention relates to a display on which broadcast signal is displayed, and more particularly, to a method for controlling an image display of other channel's broadcast signal, which is displayed on a predetermined portion of a screen.
2. Description of the Related Art
Television apparatus displays broadcast signals provided from a first transmission side (for example, broadcasting station) or signals provided from a second transmission side (for example, DVD player, computer, etc.) on screen.
Such a television apparatus includes a television set with a display, a settop box, a receive card having a function of receiving a broadcast signal, etc.
Analog television apparatus that sequentially processes analog broadcast signals has been mainly produced. However, such an analog television apparatus has a drawback in that picture quality and sound quality are degraded and channel is limited.
Accordingly, digital television apparatus that processes and displays digital broadcast signals has been developed and also available commercially.
The digital television apparatus eliminates noise that is caused by other radio waves, so that a picture quality is clear. Also, since transmission of data information is possible, a variety of additional information (for example, shopping, game, banking, news, etc.) can be provided.
Meanwhile, television apparatus provides functions of picture in picture (PIP) and picture out picture (POP), which divide one screen into several small screens. In order to support the functions, at least two tuners are needed. For example, a first broadcast signal received through a first tuner is displayed on a first divided screen, a second broadcast signal received through a second tuner is displayed on a second divided screen, and a third broadcast signal received through a third tuner is displayed on a third divided screen.
FIG. 1 is a view of a divided screen according to a conventional PIP function. FIG. 2a is a view of a divided screen according to a conventional POP function. FIG. 2b is a view of a divided screen according to an improvement of POP function in FIG. 2a. 
As shown in FIG. 1, a PIP screen includes a main screen 100 on which a main broadcast signal is displayed, and a sub screen 105 on which a sub broadcast signal is displayed. Here, the main screen 100 means a screen on which a broadcast signal a viewer now watches is displayed, and the sub screen 105 means a screen on which a broadcast signal of a channel a viewer selects through a search is displayed.
According to the PIP function, the sub screen 105 is positioned within a predetermined region of the main screen 100. Thus, the predetermined region of the main screen 100, which corresponds to the sub screen 105, is not displayed.
In the PIP screen, the sub screen 105 occupies a predetermined region of the main screen 100, so that a viewer's desire to watch the television is lowered.
In order to solve this problem, a POP function is proposed.
As shown in FIG. 2a, a POP screen includes a main screen 200 on which a main broadcast signal is displayed, and a sub screen 210 on which a sub broadcast signal is displayed. The main screen 200 occupies most of an entire region and the sub screen 210 occupies a small region, except for the region of the main screen 200.
Since the main screen 200 is not covered with the sub screen 210, a viewer's desire to watch the television is not lowered.
At this point, the sub screen 210 occupies not an entire region except for the main screen 200 but some region of the entire region except for the main screen 200.
Thus, among the entire region except for the main screen 200, a region except for the sub screen 210 exists as an empty region. An aesthetic feeling of the screen is degraded and the screen is not used efficiently owing to the empty region.
In order to solve these problems, an improved POP function is proposed. Referring to FIG. 2b, an improved POP screen is divided into a main screen 200 and a plurality of sub screens 212. Here, the sub screens 212, 214 and 216 can have the same size.
In case the POP function is applied in 16:9 wide television apparatus, it is desired that the screen be divided into three sub screens.
A main broadcast signal that a viewer is now watching is displayed on the main screen 200. Sub broadcast signals of different channels are displayed on the sub screens 212, 2147 and 216. In this manner, broadcast signals of different channels can be displayed on the main screen 200 and three sub screens 212, 214 and 216 at the same time.
In recent years, television apparatus having automatic channel searching function has been developed. Here, the automatic channel searching function means a function of tracking, selecting and displaying broadcast signals that are receivable through a tuner. For example, assuming that Ch24, Ch33, Ch38 and Ch42 are channels that are receivable through the tuner, if the television apparatus is activated to the automatic channel searching mode, Ch24, Ch33, Ch38 and Ch42 can be selected and displayed in sequence. As shown in FIG. 2b, the broadcast signals of the channels that are selected in the automatic channel searching mode can be displayed on the sub screens 212, 214 and 216. A main broadcast signal of a channel that is set as a default or is previously selected by a viewer can be displayed on the main screen 200.
According to the television apparatus having the related art POP function and automatic channel searching function, the main image and the sub images are merely displayed on the screen. Therefore, it is impossible to display the main screen and the sub screens with satisfaction to the viewer's demand. Also, a variety of viewer's searching functions cannot be satisfied within the sub screens.